WO2022063725A1

WO2022063725A1 - Method and device for detecting a short circuit in an h-bridge electronic circuit

Info

Publication number: WO2022063725A1
Application number: PCT/EP2021/075813
Authority: WO
Inventors: Baptiste ROL; Thierry BAVOIS
Original assignee: Vitesco Technologies GmbH
Priority date: 2020-09-24
Filing date: 2021-09-20
Publication date: 2022-03-31
Also published as: FR3114405A1; US20230258738A1; CN116194788A; FR3114405B1; US12196819B2

Abstract

A method for detecting a short circuit in an H-bridge electronic circuit (1), comprising the following steps: - activating a current source (17) on a first test branch; - taking a first potential measurement of one of the output terminals (6); - if the first potential measurement is substantially different from the potential of the supply terminal (3) to which the first test branch is connected, activating a current source (16) on a second, diametrically opposite test branch; - taking a second potential measurement of each output terminal (6, 7); - signalling the detection of a localised short-circuit on the output terminal whose potential resulting from the second potential measurement is closest to the potential resulting from the first potential measurement.

Description

DESCRIPTION

Title: Method and device for short-circuit detection on an H-bridge electronic circuit

TECHNICAL AREA

The invention relates to the field of electronic control of loads such as electric motors, by electronic H-bridge circuits.

PRIOR ART

H-bridges are electronic circuits widely used for controlling DC electric motors in particular. H-bridges are simple assemblies generally comprising switches such as transistors, and making it possible in particular to reverse the direction of rotation of a DC motor and to vary its speed, for example by a width modulation control pulse (PWM, "Pulse With Modulation", in English).

The detection of malfunction in this type of circuit is necessary in certain applications such as automotive applications which require precise monitoring of the operation of the controlled elements, in particular the electric motors located in the engine compartment of the vehicle. Many electric motors participate in the control of the propulsion motor of the vehicle, and the monitoring of these electric motors is related to issues of regulation, operational safety, and passenger safety.

Current methods for diagnosing prior art H-bridges are generally limited to means of detecting a dead short to a vehicle battery terminal or ground. These short-circuit detection methods generally give satisfaction for the detection of a certain number of true short-circuits but nevertheless suffer from the drawbacks listed below.

In the complex environment of automotive applications, depending on the impedance of the load being controlled, the voltage of the vehicle battery, and any current leakage, the methods of the prior art may involve random detection, leading to false diagnoses and misinterpretation of the source of the fault cause.

Moreover, when a short-circuit is detected, it is difficult to find its location on the outputs of the H-bridge. A fortiori, the physical location of the short-circuit, on the conductors in question, is excluded.

The methods of the prior art are thus not suitable for the automotive environment characterized by complexity and proximity of the wiring harnesses, and are not suitable for advanced diagnostic functions and operation in degraded mode, which require precise knowledge the location of a short circuit, in order to be able to implement palliative or corrective strategies.

DISCLOSURE OF THE INVENTION

The object of the invention is to improve the short-circuit detection means of the prior art.

To this end, the invention relates to a short-circuit detection method on an H-bridge electronic circuit which comprises:

- a high potential supply terminal;

- a low potential supply terminal;

- A first output terminal and a second output terminal intended to be connected to a load to be controlled;

- two branches on the high side, each comprising a switch connected on the one hand to the high potential supply terminal and on the other hand to one of the output terminals;

- two branches on the low side, each comprising a switch connected on the one hand to the low potential supply terminal and on the other hand to one of the output terminals.

This process comprises the following steps:

- select one of said branches as the first test branch;

- activate a current source in parallel with the switch of the first test branch, between the supply terminal and the output terminal to which the first test branch is connected;

- performing a first potential measurement consisting in measuring the potential of one of the output terminals; - if the potential resulting from this first potential measurement is substantially different from the potential of the power supply terminal to which the first test branch is connected, selecting a second test branch which is diametrically opposed to the first test branch;

- activating a current source in parallel with the switch of the second test branch, between the supply terminal and the output terminal to which the second test branch is connected, and keeping the current source of the first test branch active ;

- performing a second potential measurement consisting in measuring the potential of each output terminal;

- signal the detection of a localized short-circuit on the output terminal whose potential resulting from the second potential measurement is closest to the potential resulting from the first potential measurement.

According to another object, the invention relates to an integrated circuit comprising an H-bridge electronic circuit as well as a module adapted to implement the method described above.

The high and low potential supply terminals refer to the notions of high and low sides commonly used for H-bridges (“High side”, and “Low side”, in English).

The short-circuit detection method is a general diagnostic method for locating and identifying any anomaly affecting the H-bridge and which originates from a more or less resistive, accidental connection of two cables between them or with the mass of the vehicle. The expression "short-circuit" is used here in the broad sense and designates both a straight short-circuit (a conductor is brought back exactly to the potential of another conductor by a straight and non-resistive connection), and a short-circuit. circuit caused through a greater resistance and which modifies the value of a potential (partial insulation fault, current leakage, etc.).

The method according to the invention increases the level of reliability of the short-circuit detections as well as their accuracy. This process makes it possible to detect short-circuits affecting the H-bridge in a safe manner, to determine the type of short-circuit, as well as its position and the potential resulting from the short-circuit, even if the impedance of the controlled load is large compared to the resulting impedance of the short-circuit.

The invention can be implemented in any type of H-bridge and is particularly suited to integrated circuits bringing together an H-bridge and calculation elements making it possible to carry out both short-circuit detection according to the invention and setting. implementation of known corrective or palliative measures.

The method according to the invention may comprise the following additional characteristics, alone or in combination:

the method further comprises a step of indicating the resulting value of the detected short-circuit, this resulting value of the detected short-circuit being equal to the potential measured during the first potential measurement;

- the method comprises a step of determining the physical position of the detected short-circuit, from the identification of the output terminal on which the short-circuit is located and of said resulting value of the short-circuit;

- the first potential measurement consists in measuring the potential of the output terminal to which the switch of the first test branch is connected;

- after the step of the first potential measurement, if the potential resulting from this first potential measurement is substantially equal to the potential of the power supply terminal to which the first test branch is connected, the method comprises the following steps:

- select a third test branch which is adjacent to the first test branch and which is located on the side of the supply terminal which is opposite to the supply terminal of the first test branch;

- activate a current source in parallel with the switch of the third test branch, between the supply terminal and the output terminal to which the third test branch is connected;

- carry out a third potential measurement consisting in measuring the potential of one of the output terminals;

- if the potential resulting from this third potential measurement is substantially equal to the potential of the supply terminal to which the first test branch is connected, select a fourth test branch which is diametrically opposed to the third test branch;

- activating a current source in parallel with the switch of the fourth test branch, between the supply terminal and the output terminal to which the fourth test branch is connected, and keeping the current source of the third test branch active ;

- performing a fourth potential measurement consisting in measuring the potential of each output terminal;

- signal the detection of a localized short-circuit on the output terminal whose potential resulting from the fourth potential measurement is furthest from the potential resulting from the third potential measurement;

- after the step of the third potential measurement, if the potential resulting from this third potential measurement is substantially different from the potential of the power supply terminal to which the first test branch is connected, the method comprises a signaling step the absence of a short circuit;

the method further comprises a step of indicating the resulting value of the detected short-circuit, this resulting value of the detected short-circuit being equal to the potential measured during the third potential measurement;

- The third potential measurement consists in measuring the potential of the output terminal to which the switch of the third test branch is connected;

- the current sources have identical or different bias voltages.

PRESENTATION OF FIGURES

Other characteristics and advantages of the invention will emerge from the non-limiting description which follows, with reference to the appended drawings in which:

- [Fig.1] Figure 1 illustrates an integrated circuit according to the invention, comprising an H bridge; - [Fig.2] Figure 2 is a diagram illustrating the method according to the invention.

DETAILED DESCRIPTION

FIG. 1 represents an H-bridge electronic circuit 1, arranged on an integrated circuit 13.

In the present example, this H-bridge is provided for an automotive application and is powered by the voltage of the battery of a vehicle to control a load 12. The load 12 is, for example, an electric motor actuating a valve or a vehicle propulsion motor control flap. The load 12 can, as a variant, be constituted by any element requiring an H-bridge for its control.

The H-bridge here comprises a high potential supply terminal 2 which is connected to the positive terminal of the vehicle battery (for example, of potential +12 volts), as well as a low potential supply terminal 3 connected in this example to the mass of the vehicle.

The H-bridge thus comprises a “high side” 4 supplied by the high potential terminal 2, and a “low side” 5 supplied by the low potential terminal 3.

The H bridge comprises two output terminals 6, 7 connected to the terminals of the load 12. These output terminals 6, 7 are identified in the present description by the qualifiers "left terminal 6" and "right terminal 7", with reference to the diagram of FIG. 1.

Between each side (top 4 or bottom 5) and the output terminals 6, 7, the H bridge comprises four branches each provided with a switch 8, 9, 10, 11. In the present example, the switches, 8, 9, 10, 11 are made by transistors represented schematically in FIG. 1 by a diode and a switch (the control part of the transistors has not been shown).

In the present example, the H-bridge circuit 1 is integrated within a specialized integrated circuit 13 of the ASIC (Application Specific Integrated Circuit) type which comprises, in addition to the H-bridge, a module 14 comprising calculation means (a microcontroller, for example) adapted to control the switches 8, 9, 10, 11 and to carry out the diagnosis of the H bridge. The module 14 further comprises voltage measuring means suitable for measuring the potential of each output terminal 6, 7 of the H bridge.

The H-bridge thus comprises:

- a high side branch comprising a switch 8 connected between the high potential terminal 2 and the left output terminal 6;

- another high side branch comprising a switch 9 connected between the high potential terminal 2 and the right output terminal 7;

- a low side branch comprising a switch 10 connected between the low potential terminal 3 and the left output terminal 6;

- another low side branch comprising a switch 11 connected between the low potential terminal 3 and the right output terminal 7.

Module 14 drives switches 8, 9, 10, 11 in the conventional way for an H-bridge, depending on the command desired for load 12.

The H-bridge further comprises short-circuit detection means including four current sources 15, 16, 17, 18 each arranged in parallel with a switch s, 9, 10, 11.

In this example:

- A current source 15 is arranged in parallel with the switch 8;

- A current source 16 is arranged in parallel with the switch 9;

- A current source 17 is arranged in parallel with the switch 10;

- a current source 18 is arranged in parallel with the switch 11.

The current sources 15 to 18 are each simply represented by the symbol of a current source in series with a switch allowing it to be activated or deactivated.

The module 14 is suitable for activating a short-circuit detection mode making it possible to detect anomalies affecting the H-bridge. This short-circuit detection mode is based on the use of the current sources 15 to 18 and is set implemented when stopped, that is to say when the load 12 is not controlled. This detection mode can be activated for example each time the vehicle is powered up, as a start-up routine, or during any other stopping phase of the load 12. The H-bridge short-circuit detection method is described with reference to the diagram in Figure 2.

The method starts with a step 20 in which one of the current sources 15 to 18 is activated. For this, a branch of the H-bridge is first selected as the first test branch. Any leg of the H-bridge can be the first test leg. In the example described, the branch containing switch 10 is selected as the first test branch.

The current source 17 is therefore here activated first while the other current sources 15, 16, 18 remain deactivated.

A next step 21 consists in carrying out a first potential measurement, during which the potential of the output terminal 6 corresponding to the first test branch is measured. However, the presence of load 12 implies that the potentials of the two outputs 6, 7 are equal.

The next step 22 consists in comparing the measured potential of the output terminal 6 with the potential of the side (high or low) of the first test branch. In this example, with switch 10 connected to low side 5, the potential measured for output terminal 6 is compared to the potential of low potential terminal 3, i.e. the reference potential. If these potentials are significantly different, the method proceeds to step 23. For example, if the potential measured at the first potential measurement is located outside the range [−0.5V; +0.5V], it is considered here that it is different from 0V and the method goes to step 23. The first test branch being on the low side 5, the reference potential of 0 V is in fact the one which must be obtained during this first potential measurement, if no short circuit disturbs the H bridge.

In the case of going to step 23, the potential resulting from the first potential measurement is, as indicated above, different from the ground potential, which corresponds to an abnormal value and indicates the presence of a short-circuit which will be characterized more precisely in the remainder of the process.

During step 23, another branch of the H-bridge is selected as the second test branch. This second test branch is diametrically opposed to the first test branch. In the present example, it is the branch comprising the switch 9. The expression "diametrically opposed" here describes a element which is located on the other side (top or bottom) as well as on the other edge (right or left), with respect to a considered element.

In the example described, the current source 16 is then activated in addition to the current source 17 which remains activated, while the other current sources 15, 18 remain deactivated.

A second potential measurement is then carried out in step 24. The potential of each of the output terminals 6, 7 is measured during this step.

The next step 25 consists in comparing the potential measurements of the two terminals 6.7, resulting from the second measurement, with the potential resulting from the first measurement, and going to step 26 or to step 27 according to the following criteria:

- if the potential of the left output 6 which is measured during the second potential measurement is closer to the potential measured at the first potential measurement, than is the potential of the right output 7 which is measured during the second potential measurement, then the method goes to step 26;

- if the potential of the right output 7 which is measured during the second potential measurement is closer to the potential measured at the first potential measurement, than is the potential of the left output 6 which is measured during the second potential measurement, then the method goes to step 27.

Steps 26 and 27 relate to the location of the short-circuit, i.e. the short-circuit which was identified in step 23 will now be located: it can be located on the conductors which are connected to the left output terminal 6 or on the conductors which are connected to the right output terminal 7.

The arrival of the method at step 26 signifies that the short-circuit affects the left output 6 of the H-bridge. Step 26 then consists in signaling the detection of a short-circuit on this left output 6. This signaling can be achieved by any suitable means depending on the application, for example by activating a flag (“Flag” in English) on the module 14, adapted to be read and taken into account by corrective devices or palliatives of the vehicle (devices known and not described here).

The arrival of the method at step 27 means that the short-circuit affects the right output 7 of the H-bridge. Step 27 then consists of signaling the detection of this short-circuit on the left output 6, as before, for example by activating a flag.

In other words, the transition to steps 26 or 27 is carried out by detecting the output terminal 6, 7 whose potential resulting from the second potential measurement is closest to the potential which was measured during the first potential measurement.

In the particular case of this embodiment:

- during step 26, the potential of the left output 6 is equal to the potential resulting from the first potential measurement, while the potential of the right output 7 is different from the potential resulting from the first potential measurement;

- during step 27, the potential of the left output 6 is different from the potential resulting from the first potential measurement, while the potential of the right output 7 is equal to the potential resulting from the first potential measurement.

The short-circuit indication of step 26, respectively 27, corresponds to a situation where:

- a short circuit is present on the vehicle cables which are connected to the left output terminal 6, respectively to the right output terminal 7;

- this short-circuit presents a resultant value equal to the potential measured at the first potential measurement, i.e. the short-circuited cables present potentials leading to this resultant value, when they are shorted -circuit. The resulting value of the short-circuit thus helps to identify the cables involved in the short-circuit.

Indeed, if for example, the resulting value of the short-circuit is a potential of +12 V, this means that the output conductor connected to the output terminal in question is in full short-circuit with a conductor connected to the terminal vehicle battery positive. According to another example, if the resulting value of the short circuit is a potential of -1 V, it means that the output conductor connected to the output terminal in question is in short circuit with a conductor whose potential is lower than the circuit reference potential.

Thus, the method makes it possible to identify and locate short circuits even outside the conventional range of 0 V to 12 V, which is increasingly required in the automobile in a context of increasing complexity where many circuits may have different reference potentials, and where the body of a vehicle, taken as ground, may have different potentials in remote regions.

The method can thus comprise an additional step of determining the physical position of the short-circuit from the identification of the output terminal on which the short-circuit is located and from said resulting value of the short-circuit, that is - ie a step of identifying the electrical harness of the vehicle which is connected to the output terminal in question and which includes the cables likely to produce a short-circuit with such a resultant value. Alternatively, the current sources may have different bias voltages between them, to facilitate identification.

Moreover, contrary to what is described previously, if during step 22 the potential of the output terminal 6 measured at the first potential measurement is substantially equal to the potential of the low potential terminal 3, the The method then goes to step 28. In this example, if the potential measured at the first potential measurement is located in the range [−0.5 V; +0.5 V], the method proceeds to step 28.

Going to step 28 corresponds to the normal case of absence of short-circuit, which results in a potential of the output terminal 6 which converges suitably towards the reference potential, the first test branch being a side branch low 5. However, an ambiguity can be created by a short circuit precisely bringing the output terminal 6 back to the reference potential, regardless of whether the current source 17 is activated or not.

To increase the accuracy of the method by removing this ambiguity, it is possible, during step 28, to select a branch of the H-bridge as the test branch (it will be referred to below as the “third test branch”), this branch being adjacent to the first test branch (i.e. on the same edge, left or right), and being opposite the first test branch (i.e. on the opposite side, top or low).

In this example, the leg containing switch 8 is selected as the third test leg (this third test leg is on the high side while the first test leg was on the low side, these test being both of the same left edge). During step 28, current source 15 is then activated while the other current sources 16, 17, 18 remain deactivated.

A next step 29 consists in carrying out a potential measurement (which is qualified as a “third potential measurement” to identify it with respect to the other potential measurements of the method). This third potential measurement consists in measuring the potential of the output terminal 6 corresponding to the third test branch. As in step 21, the presence of load 12 implies that the potentials of the two outputs 6, 7 are equal.

The next step 30 consists in comparing the potential measured during the third potential measurement with the potential corresponding to the side of the first test branch. In this example, with the first test leg (switch 10) on the low side, the measured potential at output terminal 6 is compared with the potential at low potential terminal 3, i.e. the reference potential 0 V. If these potentials are substantially different, the method proceeds to step 31 . For example, if the potential measured at the third potential measurement is greater than 0.5 V, it is considered here that it is substantially different from 0 V and the method goes to step 36. The potential of 0 V is in effect that which will be obtained at the third potential measurement if a short-circuit specifically disturbs the H bridge so that the output terminals 6, 7 are constantly at the potential 0 V. When the potential resulting from the third potential measurement is thus different from the low potential 0 (and is a priori equal to +12 V), this means that this specific short-circuit is not present, and that the ambiguity mentioned above is removed. In this case, the method then goes to step 36 of the end of the method, no short-circuit having been detected.

Furthermore, if in step 30 the potential measured during the third potential measurement is equal to the potential corresponding to the side of the first test branch (0 V in this example), this means that the detection of step 22 must not conclude that there is no short-circuit because it is precisely a short-circuit artificially bringing the potential of the output terminals 6, 7 to 0 V which is responsible for this behavior. Going to step 31 corresponds to the detection of a short-circuit on one or the other of the output terminals 6, 7, this short-circuit having as resultant value the potential of 0 V. The following steps locate this short circuit.

In step 31, another leg of the H-bridge is selected as the fourth test leg. This fourth test branch is diametrically opposed to the third test branch. This example is the branch with switch 11.

In the example described, the current source 18 of the fourth test branch is therefore in turn activated, in addition to the current source 15 which also remains activated, while the other current sources 16, 17 remain deactivated.

A fourth potential measurement is then carried out in step 32, this measurement consisting in measuring the potential of each of the output terminals 6, 7.

The next step 33 consists in comparing the potential measurements of the two terminals 6.7, resulting from the fourth potential measurement, with the potential resulting from the third potential measurement (which is equal to the potential resulting from the first potential measurement , 0 V in this example), and proceed to step 34 or step 35 according to the following criteria:

- if the potential of the left output 6 which is measured during the fourth potential measurement is further from the potential measured at the third potential measurement, than is the potential of the right output 7 which is measured during the fourth potential measurement, then the method proceeds to step 34;

- if the potential of the right output 7 which is measured during the fourth potential measurement is further from the potential measured at the third potential measurement, than is the potential of the left output 6 which is measured during the fourth potential measurement, then the method proceeds to step 35.

The arrival of the method at step 34 means that the short-circuit affects the left output 6 of the H-bridge. Step 34 then consists in indicating the detection of a short-circuit on this left output 6, for example by activating a flag as before.

The arrival of the process at step 35 means that the short circuit affects the right output

7 of the H-bridge. Step 35 then consists in indicating the detection of this short-circuit on the right output 7, as before, for example by activating a flag.

In other words, the transition to steps 34 or 35 is carried out by detecting the output terminal 6, 7 whose potential resulting from the fourth potential measurement is furthest from the potential of the first and third potential measurements (0 V in this example ).

In the particular case of this embodiment:

- during step 34, the potential of the right output 7 is equal to the potential from the third potential measurement, and is substantially zero, while the potential of the left output 6 is different from zero;

- During step 35, the potential of the right output 7 is different from zero, while the potential of the left output 6 is substantially equal to zero.

The short-circuit indication of step 34, respectively 35, corresponds to a situation where:

- a short circuit is present on the vehicle cables which are connected to the left output terminal 6, respectively the right output terminal 7;

- this short-circuit has a resultant value equal to zero, i.e. the short-circuited cables have potentials leading to zero potential when they are short-circuited. The resulting value of the short-circuit thus helps to identify the cables involved in the short-circuit, that is to say in this example cables connected to the reference potential which are in contact with cables connected to the output terminal in question.

As before, the method can thus include an additional step of determining the physical position of the short-circuit from the identification of the output terminal on which the short-circuit is located and from said resulting value of the short-circuit, that is to say a step of identifying the electrical harness of the vehicle which is connected to the output terminal in question and which includes the cables at 0 V likely to produce a short-circuit with such a resulting value of 0 V Also as a variant, the current sources may have different polarization voltages between them, to facilitate identification. The method thus makes it possible to detect a short-circuit, to provide the potential resulting from the short-circuit, and to indicate the output terminal 6, 7 in question as well as the conductors in question.

The diagnostic process can start with any other of the current sources 15 to 18 than that given here as an example, as the first and third test branches, as long as the sequence proceeds in the manner described. Thus, when no short circuit is detected, the potentials of the left 6 and right 7 output terminals will be measured at 12 volts when the current sources 15 and 16 are activated, while these two potentials will be measured at 0 volts (reference potential) upon activation of the low side current sources 17, 18 5. In addition, the activation of two diametrically opposed current sources makes it possible to determine whether the resulting potential increases or decreases, which determines the edge (left or right) of the short circuit.

Furthermore, the H-bridge can be integrated into a larger bridge structure with additional switching branches.

Claims

1 . Short-circuit detection method on an H-bridge electronic circuit (1) which comprises:

- a high potential supply terminal (2);

- a low potential supply terminal (3);

- a first output terminal (6) and a second output terminal (7) intended to be connected to a load (12) to be controlled;

- two high side branches (4), each comprising a switch (8,9) connected on the one hand to the high potential supply terminal (2) and on the other hand to one of the output terminals (6.7);

- two low side branches (5), each comprising a switch (10,11) connected on the one hand to the low potential supply terminal (3) and on the other hand to one of the output terminals (6.7); said method being characterized in that it comprises the following steps:

- select one of said branches as the first test branch;

- activating a current source (17) in parallel with the switch (10) of the first test branch, between the supply terminal (3) and the output terminal (6) to which the first test branch is connected;

- carry out a first potential measurement consisting in measuring the potential of one of the output terminals (6);

- if the potential resulting from this first potential measurement is significantly different from the potential of the supply terminal (3) to which the first test branch is connected, select a second test branch which is diametrically opposed to the first branch of testing;

- activating a current source (16) in parallel with the switch (9) of the second test branch, between the supply terminal (2) and the output terminal (7) to which the second test branch is connected, and keeping active the current source (17) of the first test branch;

- performing a second potential measurement consisting in measuring the potential of each output terminal (6,7); - signaling the detection of a localized short-circuit on the output terminal whose potential resulting from the second potential measurement is closest to the potential resulting from the first potential measurement.

2. Method according to claim 1, characterized in that it further comprises a step of indicating the resulting value of the detected short-circuit, this resulting value of the detected short-circuit being equal to the potential measured during the first measurement of potential.

3. Method according to claim 2, characterized in that it comprises a step of determining the physical position of the detected short-circuit, from the identification of the output terminal on which the short-circuit is located and from said value resulting from the short circuit.

4. Method according to one of the preceding claims, characterized in that the first potential measurement consists in measuring the potential of the output terminal (6) to which the switch of the first test branch is connected.

5. Method according to one of the preceding claims, characterized in that, after the step of the first potential measurement, if the potential resulting from this first potential measurement is substantially equal to the potential of the supply terminal (3 ) to which the first test branch is connected, the method comprises the following steps:

- select a third test branch which is adjacent to the first test branch and which is located on the side (4) of the supply terminal (2) which is opposite to the supply terminal (3) of the first branch testing;

- activating a current source (15) in parallel with the switch (8) of the third test branch, between the supply terminal (2) and the output terminal to which the third test branch is connected;

- perform a third potential measurement consisting in measuring the potential of one of the output terminals (6,7);

- if the potential resulting from this third potential measurement is substantially equal to the potential of the power supply terminal (3) to which the first test branch is connected, selecting a fourth test branch which is diametrically opposed to the third branch of testing;

- activating a current source (18) in parallel with the switch (11) of the fourth test branch, between the supply terminal (3) and the output terminal (7) to which the fourth test branch is connected, and keeping active the current source (15) of the third test branch;

- performing a fourth potential measurement consisting in measuring the potential of each output terminal (6,7);

- signal the detection of a localized short-circuit on the output terminal whose potential resulting from the fourth potential measurement is furthest from the potential resulting from the third potential measurement.

6. Method according to claim 5, characterized in that, after the step of the third potential measurement, if the potential resulting from this third potential measurement is substantially different from the potential of the supply terminal (3) at which the first test branch is connected, the method includes a step of signaling an absence of short-circuit.

7. Method according to one of claims 5 to 6, characterized in that it further comprises a step of indicating the resulting value of the detected short-circuit, this resulting value of the detected short-circuit being equal to the measured potential during the third potential measurement.

8. Method according to claim 7, characterized in that it comprises a step of determining the physical position of the detected short-circuit, from the identification of the output terminal on which the short-circuit is located and of said resultant value of the short circuit.

9. Method according to one of claims 5 to 8, characterized in that the third potential measurement consists in measuring the potential of the output terminal (6) to which the switch (8) of the third test branch is connected. .

10. Method according to one of the preceding claims, characterized in that the current sources (15,16,17,18) have identical bias voltages.

11 . Method according to one of Claims 1 to 9, characterized in that the current sources (15,16,17,18) have different bias voltages.

12. Integrated circuit (13) comprising an H-bridge electronic circuit (1) and a module (14) adapted to implement the method according to one of claims 1 to 11.